It's never happens? (Hardware distraction)
It's never happens? (Hardware distraction)
Hi at all,
I ask to the ZX81 user is never happens for distraction, to insert the power jack, on the ear or the mic connector.
And sadly power up. On ear and mic connector is any type of DC block protection?
Thanks,
Matteo
I ask to the ZX81 user is never happens for distraction, to insert the power jack, on the ear or the mic connector.
And sadly power up. On ear and mic connector is any type of DC block protection?
Thanks,
Matteo
Re: It's never happens? (Hardware distraction)
Yes, surely the worst design mistake from Sinclair on the Zx81... (Spectrum?) !
Use same socket with ear/mic, and the 9v power supply…
I've been wrong many times before.
Use same socket with ear/mic, and the 9v power supply…
I've been wrong many times before.
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
Re: It's never happens? (Hardware distraction)
Thanks Xavsnap.
And this have damage your ZX81?
You have immidiately power off the brick?
Thanks.
And this have damage your ZX81?
You have immidiately power off the brick?
Thanks.
Re: It's never happens? (Hardware distraction)
I had to unplug it… no pictures !
No, the mistake seem to be … safe for the ULA ship.
C10 & C12 can isolate the ULA, but in the french display mod, the transistor TR3 can be toasted by the 9v voltage on the Mic socket.
No, the mistake seem to be … safe for the ULA ship.
C10 & C12 can isolate the ULA, but in the french display mod, the transistor TR3 can be toasted by the 9v voltage on the Mic socket.
Last edited by XavSnap on Mon Oct 19, 2020 6:42 am, edited 1 time in total.
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
Re: It's never happens? (Hardware distraction)
You have shot the ULA and the Z80?
Sorry again.
Sorry again.
Re: It's never happens? (Hardware distraction)
No, the jack return to the right place…
And the computer start properly.
But, in the real world, the Mic and the Ear jack was connect at any time, and the power socket was the only one to be feed !
No, the main problem is to invert the power supply polarity… it's a component firework… RAM, ULA, the regulator…
And the computer start properly.
But, in the real world, the Mic and the Ear jack was connect at any time, and the power socket was the only one to be feed !
No, the main problem is to invert the power supply polarity… it's a component firework… RAM, ULA, the regulator…
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
Re: It's never happens? (Hardware distraction)
Thanks so much Xavier.
Yes if you have reverse polarity is a tragedy
Thanks,
Matteo
Yes if you have reverse polarity is a tragedy
Thanks,
Matteo
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Re: It's never happens? (Hardware distraction)
Inserting the 9V DC power plug into either the Ear or Mic sockets does no harm to the ZX81. The ULA is the other side of DC blocking capacitors, so is unaffected.
Looking at the schematic for the French version, I can’t see how transistor TR3 would be damaged.
Mark
Looking at the schematic for the French version, I can’t see how transistor TR3 would be damaged.
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
Re: It's never happens? (Hardware distraction)
At a second look, the R31 resistor isn't shunted.
It's safe on the Mic socket too on the french board.
It's safe on the Mic socket too on the french board.
Xavier ...on the Facebook groupe : "Zx81 France"(fr)